The present invention relates to an engine valve operating system for an internal combustion engine, and more particularly to an engine valve operating system which operates engine valves of an internal combustion engine by means of an electromagnetic force generated by alternately energizing two electromagnets.
Various electromagnetic valve operating systems for operating engine valves have been proposed. Generally such electromagnetic valve operating systems require larger electric energy in an initializing operation for starting the valve operation as compared with the electric energy required during a valve operating period. A Japanese Patent Provisional Publication No. 59-213913 discloses an initialization method which largely improves the energy consumption necessary for executing the initializing operation of the engine valve.
However, this initialization method is required to further certainly execute the initializing operation even if the electromagnet type valve operating system employing this method is put in any condition.
It is therefore an object of the present invention to provide an engine valve operating system which is arranged to increase the attracting force of electromagnets and decrease the energy consumption during the initializing operation.
An engine valve operating system according to the present invention is for an internal combustion engine and comprises a movable member, first and second electromagnets, first and second springs, and a magnetic-circuit member. The movable member interlocks with an engine valve of the engine. The first electromagnet moves the movable member in a valve opening direction when the first electromagnet is energized. The second electromagnet moves the movable member in a valve closing direction when the second electromagnet is energized. The first spring is installed to the engine valve and applies a force directing in the valve opening direction to the movable member. The second spring is installed to said movable member and applies a force directing in the valve closing direction to the movable member. The magnetic-circuit member is connected to the first electromagnet and the second electromagnet. The magnetic-circuit member is made of soft magnetic material. The magnetic-circuit member and one of the first and second electromagnets forms a magnetic circuit when a clearance between the movable member and the one of the first and second electromagnets is within a predetermined range. The magnetic circuit passes magnetic flux from the movable member to the magnetic-circuit member.